Volatile noble metal organometallic complexes

ABSTRACT

A series of noble metal organometallic complexes of the general formula (I): ML a X b (FBC) c , wherein M is a noble metal such as iridium, ruthenium or osmium, and L is a neutral ligand such as carbonyl, alkene or diene; X is an anionic ligand such as chloride, bromide, iodide and trifluoroacetate group; and FBC is a fluorinated bidentate chelate ligand such as beta diketonate, beta-ketoiminate, amino-alcoholate and amino-alcoholate ligand, wherein a is an integer of from zero (0) to three (3), b is an integer of from zero (0) to one (1) and c is an 10 integer of from one (1) to three (3). The resulting noble metal complexes possess enhanced volatility and thermal stability characteristics, and are suitable for chemical vapor deposition(CVD) applications. The corresponding noble metal complex is formed by treatment of the FBC ligand with a less volatile metal halide. Also disclosed are CVD methods for using the noble metal complexes as source reagents for deposition of noble metal-containing films such as Ir, Ru and Os, or even metal oxide film materials IrO 2 , OsO 2  and RuO 2 .

This application is a National Stage application of PCT/CA02/01721 filedNov. 8, 2002 which claims benefit of U.S. Provisional Application60/331,157 filed Nov. 9, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a series of novel volatile noble metalorganometallic complexes, and to a method for the preparation thereof.Such complexes are particularly useful as chemical vapor deposition(CVD) precursors for formation of noble metal-containing thin films onsubstrate assemblies.

2. Description of the Prior Art

Chemical vapor deposition (hereafter indicated as “CVD”) is widely usedfor the deposition of noble metal-containing thin films on a variety ofsubstrate assemblies. CVD is a particularly attractive method forforming thin film coatings in the semiconductor industries because ithas the ability to readily control the composition of the thin film andto form a thin film layer without contamination of, or damage to thesubstrate assembly. CVD may also be applied to deposit the desired thinfilm into holes, trenches, and other stepped structures. In situationswhere conformal thin film deposition is required, CVD would also be apreferred method, since evaporation and sputtering techniques cannot beused to form a conformal thin-film layer. However, CVD processes requiresuitable source reagents that are sufficiently volatile to permit arapid transport of their vapors into the CVD reactor. The sourcereagents, which may be called the precursors, should be relativelystable and inert against oxygen and moisture in air at room temperatureto allow long-term storage. They also should decompose cleanly in theCVD reactor to deposit a high purity metal component at the desiredgrowth temperature on the substrate assembly.

The tris-acetylacetonato and tris-allyl iridium(III) complexes Ir(acac)₃and Ir(C₃H₅)₃ are two commonly known CVD precursors, for which thecommercially available Ir(acac)₃ is a better choice due to its excellentair stability. However the high melting point and low volatility ofIr(acac)₃ has limited its development as the industrial standard. Inaddition, other source reagents consist of Ir(I) metal complexes such asIr(COD)(MeCp), COD=1,4-cyclooctadiene and MeCp=methylcyclopentadienyl,Ir(COD)(hfac), hfac=hexafluoroacetylacetonate, Ir(COD)(amak),amak=OC(CF₃)₂CH₂NMe₂, [Ir(COD)(μ-OMe)]₂, [Ir(COD)(μ-OAc)]₂, OAc=acetate,and [Ir(CO)₂(μ-SBu^(t))]₂. For this family of iridium CVD precursors,the monomeric metal complexes Ir(COD)(MeCp) and Ir(COD)(hfac) appear tobe more useful for iridium deposition due to their enhanced volatilityand vapor phase transport properties which are uncomplicated bymonomer-dimer equilibria. The physical properties of these iridium CVDprecursors are listed in Table 1.

The chemical vapor deposition of osmium was achieved using thecommercially available osmocene (C₅H₅)₂Os, osmium tetraoxide OsO₄, oreven the metal carbonyl complexes such as Os(CO)₅, Os₃(CO)₁₂,Os(CO)₄(hfb), where hfb=hexafluoro-2-butyne, and the tailor-madeprecursor complexes Os(CO)₄I₂, Os(CO)₃(tfa)(hfac), tfa=trifluoroacetate,and even [Os(CO)₃(hfpz)]₂, hfpz=3,5-bis(trifluoromethyl) pyrazolate.Osmium-containing thin films with reasonable purity were obtained inmost of these studies; however, the usage of these source reagents hasencountered difficulties such as the greater toxicity for OsO₄, poorthermal stability for Os(CO)₅, and lower gas phase transportationcapability for the osmocene complex (C₅H₅)₂Os and polynuclear metalcomplex Os₃(CO)₁₂.

Moreover, the known ruthenium CVD precursor complexes includeruthenocene, Ru(C₅H₅)₂, and its alkyl substituted complexes, such asRu(C₅H₄Et)₂, carbonyl complexes, such as Ru(CO)₄(hfb),hfb=hexafluoro-2-butyne, Ru(CO)₂(hfac)₂ and Ru₃(CO)₁₂; tris-β-diketonatecomplexes, such as Ru(acac)₃, Ru(tfac)₃ and Ru(tmhd)₃; andorganometallic olefin complexes, such asbis(2,4-dimethylpentadienyl)ruthenium,bis(2,4-dimethyloxapentadienyl)ruthenium, Ru(η⁶-C₆H₆)(η⁴-C₆H₈),C₆H₈=1,3-cyclohexadiene, and Ru(COD)(C₃H₅)₂, COD=1,5-cyclooctadiene.Selected physical properties of these known osmium and rutheniumorganometallic reagents are listed in Table 2.

Accordingly, there is a continuing need for highly volatile andrelatively air and thermally stable CVD source reagents for various CVDapplications, such as the formation of bottom electrodes, diffusionbarriers, conductors, superconductors, dielectrics, capacitors,protective coatings and catalytic metal alloy films. More specifically,the iridium as well as the ruthenium source materials are becomingimportant for fabricating metallic iridium and ruthenium, iridium oxide(IrO₂) and ruthenium oxide (RuO₂) that have recently gained interest foruse as bottom electrodes in both dynamic random access memories (DRAMs)and for ferroelectric-based memory devices (FRAMs), which incorporateperovskite metal oxides as the capacitor layer. Such perovskitedielectric materials include SBT, BST, PZT, PLZT, etc., whereinSBT=strontium bismuth tantalite, BST=barium strontium titanate, PZT=leadzirconium titanate and PLZT=lead lanthanum zirconium titanate. Thepractical advantages of iridium and ruthenium based materials over otherelectrode materials include ease of deposition, good adhesion to Siwafer, the ability to form a stable conducting oxide at hightemperatures in an oxidizing environment, and the ability to operate athigh temperatures in a working device. On the other hand, osmium CVDsource reagents may find application in replacing the relatively lessstable source reagent Os(CO)₅ or the highly toxic compound OsO₄ formaking the osmium-coated thermionic cathodes and abrasive-resistantosmium hard-coatings.

Generally speaking, CVD of these metal-containing thin film coatings hasbeen limited due to a variety of reasons, including formation of poorfilm quality, requiring of high processing temperatures, lack ofsuitable precursor compounds, and instability of the precursors used inthe deposition systems. The availability of suitable precursors withmoderate volatility and stability appears to be the greatest limitingfactors in the CVD applications, as the poor stability against heat andmoisture makes them difficult to store and handle, yields inferior thinfilm coatings and creates serious contamination at the as-deposited thinfilms in production-scale operations.

It is therefore an object of the present invention to provide suitablenovel CVD precursors that are amenable to use in the chemical vapordeposition of noble metal-containing films.

Based on the need for these noble metal-containing coatings, the priorart has sought to provide new design for the suitable CVD precursors andcontinued to seek improvements in their basic physical properties thatare advantageous for integration with current CVD technology.

It is another object of the present invention is to provide a simplifiedCVD method for forming a noble metal-containing film on a substrateassembly utilizing these newly prepared precursors. Other objects,features, and advantages will be more fully apparent from the ensuingdisclosure and appended claims.

TABLE 1 Selected physical properties of known iridium CVD precursorsCompound M.P. (° C.) CVD T_(D) (° C.) Sublimation Condition ReferencesIr(acac)₃ 300–400° C. subl. at 180–200° C. (a) Ir(C₃H₅)₃ dec. at 65° C.100° C. subl. at 50° C./15 torr (b) Ir(COD)(MeCp) 38–40° C. 270–350° C.subl. at 95° C./0.05 torr (c) and (d) Ir(COD)(hfac) 120° C. 250–400° C.subl. at 60° C./0.05 torr (e) Ir(COD)(amak) 127° C. 350° C. subl. at 50°C./0.2 torr (f) [Ir(COD)(μ- 135° C. 250° C. subl. at 125° C./0.07 torr(c) OAc)]₂ [Ir(CO)₂(μ-SBu^(t))]₂ 128° C.; dec. 160° C. 150–450° C. subl.at 80–140° C./0.1 torr (f) Abbreviations: T_(D) = depositiontemperature, acac = acetylacetonate, C₃H₅ = allyl, MeCp =methylcyclopentadienyl, hfac = hexafluoroacetylacetonate, amak =OC(CF₃)₂CH₂NMe₂, COD = 1,5-cyclooctadiene, OAc = acetate. (a) Sun,Y.-M.; Endle, J. P.; Smith, K.; Whaley, S.; Mahaffy, R.; Ekerdt, J. G.;White, J. M.; Hance, R. L. Thin Solid Films 1999, 346, 100. (b) Kaesz,H. D.; Williams, R. S.; Hicks, R. F.; Zink, J. I.; Chen, Y.-J.; Muller,H.-J.; Xue, Z.; Xu, D.; Shuh, D. K.; Kim, Y. K. New. J. Chem. 1990, 14,527. (c) Hoke, J. B.; Stern, E. W.; Murray, H. H. J. Mater. Chem. 1991,1, 551. (d) Sun, Y.-M.; Yan, X.-M.; Mettlach, N.; Endle, J. P.; Kirsch,P. D.; Ekerdt, J. G.; Madhukar, S.; Hance, R. L.; White, J. M. J. Vac.Sci. Technol. 2000, 18, 10. (e) Xu, C.; Baum, T. H.; Rheingold, A. L.Chem. Mater. 1998, 10, 2329. (f) Chen, Y.-L.; Liu, C.-S.; Chi, Y.;Carty, A. J.; Peng, S.-M.; Lee, G.-H. Chem. Vap. Deposition 2002, 8, 17.(g) Serp, P.; Feurer, R.; Kalck, P.; Gomes, H.; Faria, J. L.;Figueiredo, J. L. Chem. Vap. Deposition 2001, 7, 59.

TABLE 2 Relevant physical properties of selective known osmium andruthenium CVD precursors Compound M.P. (° C.) CVD T_(D) (° C.) Relativevolatility References Osmocene 194–198 350–500° C. (a) Os₃(CO)₁₂226–228° C. 225° C. vaporized at 50° C. (b) Os(CO)₄(hfb) 600° C. subl.at 25° C./0.05 torr (c) Os(CO)₄I₂ 450–550° C. subl. at 55° C./0.45 torr(d) Os(CO)₃(tfa)(hfac) 153–156° C. 400–500° C. subl. at 55° C./0.45 torr(d) [Os(CO)₃(hfpz)]₂ 189° C. 400–550° C. vaporized at 110° C. (e)Ruthenocene 194–198 225–500° C. yap, pressure 0.01 torr at (a) and (f)85° C. Ru₃(CO)₁₂ 150 dec. 150–175° C. vaporized at 50° C. (b)Ru(CO)₄(hfb) 200–500° C. subl. at 25° C./0.05 torr (c) Ru(tmhd)₃ 210–213250–600° C. subl. at 120° C./0.5 torr (g) Ru(COD)(C₃H₅)₂ 300° C.vaporized at 75° C. (h) Ru(CO)₂(hfac)  55–75° C. 400° C. vaporized at50° C. (i) RuO₄  27° C. 150–220° C. b.p. = 129° C. highly toxic, (j)Abbreviation: T_(D) = deposition temperature, hfb = hexafluoro-2-butyne,tfa = trifluoroacetate, hfac = hexafluoroacetylacetonate, hfpz =3,5-bis(trifluoromethyl) pyrazolate, tmhd =2,2,6,6-tetramethyl-3,5-heptanedionate, C₃H₅ = allyl and COD =1,5-cyclooctadiene. (a) Smart, C. J.; Gulhati, A.; Reynolds, S. K.Mater. Res. Soc. Symp. Proc. 1995, 363, 207. (b) Boyd, E. P.; Ketchumn,D. R.; Deng, H.; Shore, S. G. Chem. Mater. 1997, 9, 1154. (c) Seuzaki,Y.; Gladfelter, W. L.; McCormick, F. B. Chem. Mater. 1993, 5, 1715. (d)Yu, H.-L.; Chi, Y.; Liu, C.-S.; Peng, S.-M.; Lee, G.-H. Chem. Vap.Deposition 2001, 7, 245. (e) Chi, Y.; Yu, H.-L.; Cling, W.-L.; Liu,C.-S.; Chen, Y.-L.; Chou, T.-Y.; Peng, S.-M.; Lee, G.-H. J. Mater. Chem.2002, 12, 1363. (f) Park, S.-E.; Kim, H.-M.; Kim, K.-B.; Min, S.-H. J.Electrochem. Soc. 2000, 147, 203. (g) Vetrone, J.; Foster, C. M.; Bai,G.-R.; Wang, A.; Patel, J.; Wu, X. J. Mater. Res. 1998, 13, 2281. (h)Barreca, D.; Buchberger, A.; Daolio, S.; Depero, L. E.; Fabrizio, M.;Morandini, F.; Rizzi, G. A.; Sangaletti, L.; Tondello, E. Langmuir 1999,15, 4537. (i) Lee, F.-J.; Chi, Y.; Hsu, P.-F.; Chou, T.-Y.; Liu, C.-S.;Peng, S.-M.; Lee, G.-H. Chem. Vap. Deposition 2001, 7, 99. (j) Sankar,J.; Sham, T. K.; Puddephatt, R. J. J. Mater. Chem., 1999, 9, 2439.

SUMMARY OF THE INVENTION

According to one aspect of the invention we provide, a novel noble metalorganometallic complex of general formula (I):[ML_(a)X_(b)(FBC)_(c)]  (I)wherein M is a noble metal; L is a neutral ligand selected from thegroup consisting of carbonyl, alkene, diene and derivatives of alkenesand dienes additionally containing alkyl or fluorinated alkylsubstituents; X is an anionic ligand such as chloride, bromide, iodideand trifluoroacetate group; wherein a is an integer of from zero (0) tothree (3), b is an integer of from zero (0) to one (1) and c is aninteger of from one (1) to three (3); FBC ligand is a fluorinatedbidentate chelate ligand such as a beta-diketonate (FBC1),beta-ketoiminate (FBC2), imino-alcoholate (FBC3) and amino-alcoholate(FBC4) having the structural formula indicated below:

wherein R is a C1–C4 alkyl group such as methyl and t-butyl, ortrifluoromethyl; R¹ is a C1–C6 alkyl group e.g. methyl, ethyl, allyl,n-propyl, i-propyl, n-butyl and i-butyl, which may be substituted by aC1–C4 alkoxy group, and wherein FBC4, one of the R¹ groups may be H.

It will be appreciated by those skilled in the art that, havingestablished by example that the nitrogen atom of the FBC4 ligandrequires two R¹ groups to fulfill its trivalent structure, that one ofthe R¹ groups can be replaced by a hydrogen atom, because of the similarchemical behavior between hydrogen atoms and alkyl substituents in thissystem.

The noble metal is preferably iridium, ruthenium or osmium.

According to another aspect of the invention, we provide a method formaking a novel noble metal organometallic complex of general formula(I), comprising (a) reacting the respective FBC ligand with a suitablemetal hydride e.g. sodium hydride, followed by (b) treatment of theproduct so formed with a metal halide salt of the desired metal.

The preferred metal halide salts include [Ir(COD)(μ-Cl)]₂,COD=1,5-cyclooctadiene, [Os(CO)₃(μ-X)]₂, X=CF₃CO₂, Cl, Br and I,[Ru(COD)Cl₂]_(x) and [Ru(NBD)Cl₂]_(x), COD=1,5-cyclooctadiene andNBD=2,5-norbornadiene.

The FBC ligands are characterized in that they are highly fluorinatedand contain oxygen or nitrogen donor atoms. Despite the obviousdifference in their structural design, this class of ligand can becovalently coordinated to the central metal atom to form the stablechelate interaction. The ligand fragment “(FBC1)” represents the typicalfluorinated beta-diketonate group, wherein R is a C1–C4 alkyl group e.g.methyl, t-butyl, or trifluoromethyl; R¹ is a C1–C6 alkyl group e.g.methyl, ethyl, allyl, n-propyl, i-propyl, n-butyl and i-butyl, or2-methoxyethyl. The second ligand fragment “(FBC2)” represents thebeta-ketoiminate fragment which can be prepared from the reaction ofneutral (BFC1)H with an organic amine H₂NR¹ in the presence of a solidacid catalyst such as montmorillonite K10. The third and the fourthligand group “(BFC3)” and “(BFC4)” belong to a new class offluoroalcohol molecules with a pendant amine that can bend back andforming a strong dative interaction to the central metal atom, and areprepared according to literature methods. Moreover, because of thepresence of at least one electronegative trifluoromethyl (CF₃)substituent on each of the FBC ligands, the ligands as well as theresulting metal complexes are chemically stable and can be easilyvolatilized into the gas phase. It is well understood that the CF₃substituents have the capability to reduce the Van der Waalsinteractions between individual molecules and hence lower the boiling orsublimation temperature of the complex.

The respective ligands are either purchased from the commercial supplieror synthesized according to the literature procedures.

In another aspect, the invention relates to the use of the novel noblemetal organometallic complex of the general formula ML_(a)X_(b)(FBC)_(c)(I) as a source reagent for chemical vapor deposition(CVD) applications.Thus, the noble metal complex is charged into a source reservoir of aCVD reactor to deposit the noble metal-containing thin-film on asubstrate assembly.

In accordance with the invention, the iridium, ruthenium or osmium thinfilm material is formed on the substrate by depositing any one of thenovel iridium, ruthenium or osmium source reagents of formula I under aninert atmosphere, such as N₂, He or Ar, or in the presence of reducingcarrier gas such as H₂. The resulting iridium, ruthenium or osmium layermay be converted to IrO₂, RuO₂ or OsO₂ thin film in an oxygen-containingatmosphere at the elevated temperature. In a like manner, the IrO₂, RuO₂or OsO₂ thin film material may be prepared by depositing either one ofthe iridium, ruthenium or osmium source reagents on the substrate underthe oxygen-containing atmosphere or under the condition where anoxygen-containing plasma is applied.

Such chemical vapor deposition conditions may advantageously comprisethe presence of the gaseous co-reagent or carrier gas commonly utilizedin CVD applications. For example, the employment of an inert gasatmosphere or a slow stream of inert carrier gas such as N₂, He and Ar,or a reducing carrier gas such as H₂, favors the formation of pureiridium, ruthenium and osmium thin films on substrates. On the otherhand, the introduction of high concentrations of an oxygen-containingatmosphere or oxidizing carrier gas such as O₂, or N₂O may lead to theformation of Ir/IrO₂ mixture, Ru/RuO₂ mixture, Os/OsO₂ mixture or evenhigh purity IrO₂, RuO₂ or OsO₂ films at a higher deposition temperature,or upon increasing the deposition time as well as the partial pressureof the oxidizing carrier gas.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a three-dimensional illustration of an iridium complex[Ir(CO)₂(FBC4)] according to the invention;

FIG. 2 is a three-dimensional illustration of a ruthenium complex[Ru(NBD)(FBC1)₂] with only two (FBC) ligands;

FIG. 3 is a three-dimensional illustration of a ruthenium complex[Ru(FBC2)₃] showing three (FBC2) ligands; and

FIG. 4 is a three-dimensional illustration of an osmium complex[Os(CO)₃I(FBC1)] according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

A. Iridium Precursors

In the present invention, neutral iridium precursors are chosen from ageneral class of compound of formula (II) (III) and (IV):[IrL_(a)(FBC2)]  (II),[IrL_(a)(FBC3)]  (III)and[IrL_(a)(FBC4)]  (IV)wherein L is a neutral ligand selected from the group consisting ofcarbonyl, alkene, diene or derivatives of alkenes and dienesadditionally containing at least one alkyl or fluorinated alkylsubstituent; a is an integer of one or two, depending on the donorbonding of the selected ligand; FBC2 ligand is a fluorinated bidentatechelate ligand such as a beta-ketoiminate, imino-alcoholate (FBC3) andamino-alcoholate (FBC4) having the structural formula indicated below:

wherein R is C1–C4 alkyl, e.g. methyl or t-butyl, or trifluoromethyl; R¹is C1–C6 alkyl e.g. methyl, ethyl, allyl, n-propyl, i-propyl, n-butyl ori-butyl, which may be substituted by a C1–C4 alkoxy group e.g.2-methoxyethyl, and wherein FBC4, one of the R¹ groups may be H.

It will be appreciated by those skilled in the art that, havingestablished by example that the nitrogen atom of the FBC4 ligandrequires two R¹ groups to fulfill its trivalent structure, we cansubstitute one of the R¹ groups by a hydrogen atom, because of thesimilar chemical behavior between a hydrogen atom and an alkylsubstituent in this system.

Broadly, iridium complexes of formula (II), (III) and (IV) may beprepared by the direct chloride exchange reaction as show in equations[1], [2] and [3]:[Ir(COD)(μ-Cl)]₂+2(FBC2)Na→2[Ir(COD)(FBC2)]+2NaCl  [1][Ir(COD)(μ-Cl)]₂+2(FBC3)Na→2[Ir(COD)(FBC3)]+2NaCl  [2][Ir(COD)(μ-Cl)]₂+2(FBC4)Na→2[Ir(COD)(FBC4)]+2NaCl  [3]

Thus, the neutral ligand “L_(a)” of formula (II), (III) and (IV) in thiscase is the COD ligand, in which both of the alkene functional groupsform strong bonding interactions to the central iridium atom. Inaddition, subsequent treatment of [Ir(COD)(FBC2)], [Ir(COD)(FBC3)] or[Ir(COD)(FBC4)] with carbon monoxide atmosphere at elevated temperaturegives the corresponding CO substituted complex [Ir(CO)₂(FBC2)],[Ir(CO)₂(FBC3)] or [Ir(CO)₂(FBC4)], respectively; and the COD ligand isnow replaced by two carbon monoxide ligands; the stoichiometrictransformation is indicated in the following equations [4], [5] and [6].[Ir(COD)(FBC2)]+2CO→2[Ir(CO)₂(FBC2)]+COD  [4][Ir(COD)(FBC3)]+2CO→2[Ir(CO)₂(FBC3)]+COD  [5][Ir(COD)(FBC4)]+2CO→2[Ir(CO)₂(FBC4)]+COD  [6]

As a result, the neutral ligand “L” of formula (II), (III) and (IV)represents a CO ligand and a is now two (2). Selected physicalproperties of these iridium complexes are summarized in Table 3. It isimportant to note that these iridium complexes [IrL_(a)(FBC2)] (II),[IrL_(a)(FBC3)] (III) and [IrL_(a)(FBC4)] (IV) are all relatively stableat room temperature in air and they can be handled in the absence of aninert atmosphere such as nitrogen and argon. The ability to vary thesubstituents on all three FBC ligands provides an excellent degree ofcontrol over both volatility and the deposition parameters for therespective CVD experiments. Moreover, replacement of COD with twocarbonyl ligands has substantially increased the volatility andstability of these precursor compounds. Thus, the choice of the “L_(a)”groups can also have a significant influence on their basic properties.

A single crystal X-ray diffraction study of compound [Ir(CO)₂(FBC4)]with the substituents R¹=Me was carried out, revealing the square planararrangement of the iridium metal center alone with two cis-CO ligandsand the corresponding fluorinated bidentate chelate ligand. The ORTEPrepresentation of the molecular structure is shown in FIG. 1.

Specifically, the molecular structure of the complex [Ir(CO)₂(FBC4)]with R¹=Me; selected bond distances: Ir—C1=1.818 Å, Ir—C2=1.838 Å,Ir—O1=1.990 Å, Ir—N1=2.132 Å, selected bond angles: C1-Ir—C2=88.73°,C1-Ir—O1=177.06°, C2-Ir—O1=94.07°, C1-Ir—N1=96.13°, C2-Ir—N1=175.13°,N1-Ir—O1=81.06°.

B. Ruthenium Precursors

The identical synthetic strategy can be extended to a reaction using theruthenium halide compound [RuL_(a)Cl₂]_(x), and upon treatment with therespective fluorinated ligand salt FBC1)Na, (FBC4)Na and (FBC2)Na, theneutral ruthenium precursors of formula (V), (VI) and (VII):[RuL_(a)(FBC1)₂]  (V),[RuL_(a)(FBC4)₂]  (VI)and[Ru(FBC2)₃]  (VII)are obtained in moderate yields;wherein L is a neutral ligand selected from the group consisting of acyclic diene such as COD or NBD, or derivatives of a cyclic dieneadditionally containing at least one alkyl or fluorinated alkylsubstituent; a is one or zero, depending on the (FBC) ligand selectedfor the reactions; FBC ligand is a fluorinated bidentate chelate ligandsuch as beta-diketonate (FBC1), beta-ketoiminate (FBC2) andamino-alcoholate (FBC4) having structural formula indicated below:

wherein R is a C1–C4 alkyl group e.g. methyl, t-butyl andtrifluoromethyl; R¹ is a C1–C6 alkyl group e.g. methyl, ethyl, allyl,n-propyl, i-propyl, 2-methoxyethyl, n-butyl and i-butyl. Moreover, it isimportant to note that the nitrogen atom of the aminoalcoholate ligand(FBC4) requires at least one hydrogen substituent; otherwise, no stableruthenium product can be isolated.

Using the ruthenium complex [Ru(COD)Cl₂]_(x) as an example to illustratethe previously discussed procedure, the ruthenium metal complexes ofgeneral formulas (V), (VI) and (VII) may be obtained by a directreaction as shown in the following equations [7], [8] and [9]:1/x[Ru(COD)Cl₂]_(x)+2(FBC1)Na→[Ru(COD)(FBC1)₂]+2NaCl  [7]1/x[Ru(COD)Cl₂]_(x)+2(FBC4)Na→[Ru(COD)(FBC4)₂]+2NaCl  [8]1/x[Ru(COD)Cl₂]_(x)+3(FBC2)Na→[Ru(FBC2)₃]+COD+3NaCl  [9]

In addition, specific example of neutral ligand “L” of formula (V) and(VI) in this case include COD or NBD, i.e. 1,5-cyclooctadiene or2,5-norbornadiene, in which the alkene C—C double bonds of the COD orNBD ligand are strongly coordinated to the ruthenium atom, while that ofthe formula (VII) shows the co-existence of three fluorinated bidentatechelate ligands (FBC2), without the neutral donor ligand residing in thecoordination sphere of the ruthenium atom, as the ruthenium metal hasinadvertently oxidized from +2 to +3 oxidation state during thereaction. Selected physical properties of these ruthenium complexes aresummarized in Table 4.

To further illustrate the feasibility of this invention, the structureof the complex [Ru(NBD)(FBC1)₂] wherein R=CF₃ is confined by singlecrystal X-ray diffraction analysis (FIG. 2). It consists of anoctahedral environment with one NBD and two hfac chelate ligands.Moreover, all Ru—O(hfac) bond distances are within a narrow range2.077(2)˜2.086(2) Å, exhibiting no obvious difference between the twodissimilar Ru—O fragments, the first is trans to the C—C double bond ofthe NBD ligand, while the other is trans to the second Ru—O(hfac)vector. This observation is in contrast to that of the carbonyl complex[Ru(CO)₂(hfac)₂], in which the Ru—O distances trans to the CO ligand(2.075(2) and 2.081(2) Å) are found to be slightly longer than the othertwo Ru—O distances (2.050(2)˜2.052(2) Å), showing a thermodynamiclabilization effect imposed by the CO ligands.

Specifically, the molecular structure of the complex [Ru(NBD)(FBC1)₂]with R=CF₃; selected bond distances: Ru—O1=2.083 Å, Ru—O2=2.084 Å,Ru—O3=2.077 Å, Ru—O4=2.086 Å, Ru—C1=2.183 Å, Ru—C2=2.178 Å, Ru—C4=2.189Å, Ru—C5=2.187 Å, selected bond angles: O1-R—O3=167.40°, O3-R—O2=80.03°,O3-R—O4=89.90°, O3-R—O4=89.90°, O1-R—O2=89.57°, O1-R—O4=82.55°.

The structure of the second type of precursor complex with formula[Ru(FBC2)₃] wherein R=CF₃ and R¹=Me, is also determined by X-raydiffraction analysis. As indicated in FIG. 3, the complex adopts anoctahedral ligand arrangement, and the unsymmetrical bidentate chelateligands are situated around the ruthenium atom to give the meridionalgeometry. This X-ray structure confirms that the asymmetric FBC2 ligandis capable of imposing the meridional geometry about the metal center,to the total exclusion of the facial isomer that would exhibit a largesteric interaction between the R¹ substituent of all three FBC2 ligands.

Specifically, the structure of the precursor complex with formula[Ru(FBC2)₃] with R=CF₃ and R¹=Me; selected bond distances: Ru—O1=2.015Å, Ru—O2=1.984 Å, Ru—O3=2.013 Å, Ru—N1=2.090 Å, Ru—N2=2.037 Å,Ru—N3=2.042 Å, selected bond angles: O2-Ru—O1=174.45°, O3-Ru—N2=173.54°,N3-Ru—N1=174.00°.

C. Osmium Precursors

In yet another aspect of the invention, the osmium CVD precursors of thegeneral formula (VIII):[OsL_(a)X(FBC)]  (VIII)are obtained;wherein L represents carbonyl ligand; a has a constant value of three, Xis an anionic monodentate ligand such as chloride, bromide, iodide ortrifluoroacetate, FBC ligand is a fluorinated bidentate chelate ligandsuch as a beta-diketonate group (FBC1). Preferred beta-diketonateligands (ABCB) include: (hfac)=hexafluoroacetylacetonate,(tfac)=trifluoroacetylacetonate, and(tdhd)=1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionate.

A useful synthetic procedure for this compound involves direct heatingof a mixture of osmium halide salt [Os(CO)₃(μ-X)]₂ and at least twoequivalents of the fluorinated chelate ligand (FBC1)H sealed in a Cariustube. The tube is then heated at 180° C. for 6 hours to ensure thecompletion of reaction. This process is best illustrated by the proposedstoichiometric transformation, as shown in equation [10]:[Os(CO)₃(μ-X)]₂+2(FBC1)H→2[Os(CO)₃X(FBC1)]+H₂  [10]

Due to the lower chemical reactivity of osmium compound [Os(CO)₃(μ-X)]₂,three other fluorinated bidentate chelate ligands (FBC)H have failed toexhibit a similar reaction pattern and thus, afforded no isolableproduct that can serve as the required osmium CVD precursor. Moreover,all attempts to generate the complex of formula [Os(CO)₂(FBC1)₂] byemploying a large excess of the (FBC1) ligand have failed, and onlyafforded the known mono-substituted product [Os(CO)₃X(FBC1)].

The product complexes of formula [Os(CO)₃X(FBC1)] are readilycharacterized using mass spectrometry (MS), nuclear magnetic resonancespectroscopy (NMR), infrared spectroscopy (IR), single crystal X-rayanalysis, elemental analysis, and thermal gravimetric analysis (TGA).Selected physical properties of the ruthenium and osmium source reagentsof the present invention are summarized in Table 5. The structure of thecomplex [Os(CO)₃I(FBC1)] where R¹=t-butyl is determined by singlecrystal X-ray diffraction. Its ORTEP representation is depicted in FIG.4 to show the octahedral arrangement of ligands.

Specifically, the ORTEP representation of the complex [Os(CO)₃I(FBC1)]with R¹=t-butyl; selected bond distances: Os—C1=1.883 Å, Os—C2=1.911 Å,Os—C3=1.914 Å, Os—O4=2.069 Å, Os—O5=2.092 Å, selected bond angles:Os—I1=2.722 Å, C1-Os—O4=175.09°, C2-Os—O5=176.34°, O5-Os—O4=87.74°,C3-Os—I1=179.68°.

TABLE 3 Physical properties of the iridium CVD precursors of the presentinvention M. P. % Entry Compound (° C.) sublim. cond. T_(1/2) (° C.)^(a)Residue^(b) 1 [Ir(COD)(FBC2)]; R = CF₃, R¹ = Me 78 57° C./0.1 torr 21010.0 2 [Ir(COD)(FBC2)]; R = CF₃, R¹ = Et 111 50° C./0.14 torr 193 17.3 3[Ir(COD)(FBC3)]; R¹ = Me 166 65° C./0.1 torr 230 34.5 4 [Ir(COD)(FBC3)];R¹ = n-Pr 117 43° C./0.12 torr 245 25.9 5 [Ir(COD)(FBC4)]; R¹ = Me 12757° C./0.15 torr 213 12.4 6 [Ir(CO)₂(FBC2)]; R = CF₃, R¹ = n-Bu 141 45°C./4 torr 151 0.3 7 [Ir(CO)₂(FBC3)]; R¹ = n-Pr 88 41° C./0.8 torr 2010.9 8 [Ir(CO)₂(FBC4)]; R¹ = Me 104 42° C./3 torr 174 0.1 ^(a)Thetemperature at which 50 wt. % of the sample has been lost during TGAanalysis (heating rate = 10° C./min and N₂ flow rate = 100 cm³/min).^(b)Total weight percent of the sample observed at 500° C. during TGAanalysis. c) Melting-point is greater than decomposition temperature.

TABLE 4 Physical properties of the ruthenium and osmium CVD precursorsof the present invention M. P. T_(1/2) % Entry Compound (° C.) sublim.cond. (° C.) Residue 9 [Ru(NBD)(FBC1)₂], R = CF₃ 82  45° C./0.15 torr157 3.0 10 [Ru(COD)(FBC4)₂], R¹ = H 288 150° C./0.25 torr 288 19.6 11[Ru(COD)(FBC4)₂], R¹ = Et 198  90° C./0.25 torr 229 15.7 12 [Ru(FBC2)₃],R = CF₃, R¹ = Me 127  60° C./0.40 torr 172 2.1 13 [Ru(FBC2)₃], R = Me,R¹ = Me 196  60° C./0.20 torr 262 1.7 14 [Os(CO)₃(CF₃CO₂)(FBC1)], R =CF₃ 150  55° C./0.45 torr 152 5.0 15 [Os(CO)₃(CF₃CO₂)(FBC1)], R = t-Bu71  45° C./0.22 torr 163 2.8 16 [Os(CO)₃Br(FBC1)], R = t-Bu 127  70°C./0.25 torr 165 2.3 17 [Os(CO)₃I(FBC1)], R = t-Bu 109  55° C./0.12 torr163 1.2D. CVD Experiments

The above-mentioned iridium, ruthenium and osmium complexes have beenfound to be well suited as precursors for CVD applications because theymeet the following criteria: (a) they have high vapor pressure at atemperature of below 180° C., which is essential to enable a sufficientamount of the reagent vapor to be transported into the CVD reactor atthe temperature convenient for CVD processing, in an inert gas or othercarrier gas stream, (b) they are thermally stable below the temperatureof about 180° C., and therefore do not decompose in the CVD system, and(c) they can cleanly decompose on substrates to deposit the desiredcomposition with little or no incorporation of carbon, nitrogen andfluorine impurities.

Based on the physical data summarized in Tables 3 and 4, the CVDprecursors according to this invention include the following advantages:

A. Higher thermal and oxidative stability in air.

The noble metal CVD precursors containing at least one CF₃ substituentcan be handled in air at room temperature without showing significantdecomposition.

B. Possibility of serving as a liquid CVD precursor.

Complexes 1, 7, 9 and 15 which exhibit a relatively lower melting pointat below 88° C., can be used as a liquid precursor if the reservoirtemperature is kept above its melting point.

C. Enhanced vapor pressure under the designated CVD conditions.

Most of these noble metal CVD precursors can be sublimed without showingsignificant decomposition at around 400 mtorr and at a temperature below100° C.

D. Possibility of fine-tuning their physical properties.

The relative stability of these fluorinated chelate complexes isdetermined by the intrinsic bonding characteristics between the metaland the coordinative ligand. This invention provides four differenttypes of FBC ligands that can form the required noble metal CVDprecursors. Thus, selection of the best CVD precursors suited to therespective commercial processes is possible. Moreover, it is wellunderstood that, by increasing the number of CF₃ substituent on the FBCligands, the volatility of the resulting CVD precursors would improvesubstantially. On the other hand, increasing the chain length of the R¹substituent on the nitrogen atom of the FBC ligands would reduce thevolatility and decrease the melting point of the precursors.

EXPERIMENTAL SECTION

Without intending to limit it in any manner, the present invention willbe further illustrated by the following examples.

Example 1

Synthesis of [Ir(COD)(FBC2)₂], R=CF₃, R¹=Et.

Sodium hydroxide (24 mg, 1.0 mmol) was suspended in 20 mL of THF. Tothis was slowly added 0.15 g of ketoimine ligand HOC(CF₃)═CHC(CF₃)═NEt(0.64 mmol) in THF (20 mL). The mixture was stirred at room temperaturefor 40 min. The solution was then filtered and the filtrate wastransferred into a 100 mL reaction flask containing a suspension of[Ir(COD)(μ-Cl)]₂ (0.2 g, 0.29 mmol) in THF (50 mL). This mixture wasstirred at room temperature for 4 hours, giving a dark-red solutionalone with an off-white NaCl precipitate. THF was removed under vacuumand the resulting oily residue was taken into 35 mL of hexane. Thesolution was washed with distilled water (2×20 mL), and then treatedwith drying agent Na₂SO₄, evaporation of hexane and sublimation at 50°C. and 140 mtorr to give 0.23 g of dark red iridium compound[Ir(COD){HOC(CF₃)═CHC(CF₃)═NEt}] (0.43 mmol, 74%).

Spectral data: MS (EI, ¹⁹³Ir), m/z 535, M⁺. ¹H NMR (CDCl₃, 333 K): δ6.03 (s, 1H, CH), 4.48 (br, 2H, CH_((COD))), 3.44 (br, 2H, CH_((COD))),3.39 (br, 2H, CH₂), 2.14˜1.93 (m, 4H, CH_(2(COD))), 1.53 (br, 4H,CH_(2(COD))), 1.06 (t, 3H, ³J_(HH)=7 Hz, CH₃). ¹³C NMR (C₆D₆, 333 K): δ164.2 (q, 1C, ¹J_(CF)=26 Hz, CO), 164.2 (q, 1C, ¹J_(CF)=28 Hz, CN),120.7 (q, 1C, ¹J_(CF)=227 Hz, CF₃), 120.3 (q, 1C, ^(J) _(CF)=224 Hz,CF₃), 91.6 (s, 1C, CH), 69.9 (s, 2C, CH_((COD))), 58.1 (br, 2C,CH_((COD))), 48.8 (s, 1C, NCH₂), 32.6 (s, 2C, CH_(2(COD))), 29.3 (s, 2C,CH_(2(COD))), 20.7 (s, 1C, CH₃). ¹⁹F NMR (C₆D₆, 298K): δ −62.15 (s, 3F,OCCF₃), −73.07 (s, 3F, NCCF₃). Anal. Calcd. for C₁₅H₁₈F₆IrNO: C, 33.71;H, 3.39. Found: C, 33.47; H, 3.41.

Example 2

Synthesis of [Ir(COD)(FBC3)₂], R¹=Pr.

The preparation procedures were identical to that of example 1, using0.2 g of [Ir(COD)(μ-Cl)]₂ (0.29 mmol), 0.17 g of iminoalcoholHO(CF₃)₂CH₂N(Me)═NPr (0.64 mmol), 0.1 g of NaOH and 50 mL of THF. Forwork-up, the reaction mixture was extracted with hexane, followed bydrying and evaporation of hexane, the solid residue was then purified byvacuum sublimation (120 mtorr, 43° C.), giving 0.28 g of yolk yellow[Ir(COD){O(CF₃)₂CH₂N(Me)═NEt}] (0.50 mmol, 86%).

Spectral data: MS (EI, ¹⁹³Ir), m/z 565, M⁺. ¹H NMR (C₆D₆, 298K): δ4.50˜4.48 (m, 2H, CH), 3.02˜2.98 (m, 2H, CH), 2.80 (t, 2H, ¹J_(HH)=8 Hz,NCH₂), 2.70 (s, 2H, CH₂), 2.23˜2.10 (m, 4H, CH_(2(COD))), 1.51˜1.39 (m,6H, CH_(2(COD)) & NCH₂CH₂), 1.27 (s, 3H, CH₃), 0.64 (t, 3H, ¹J_(HH)=7.2Hz, NCH₂). ¹³C NMR (CDCl₃, 298K): δ 176.0 (s, 1C, CN), 125.5 (q, 2C,¹J_(CF)=292 Hz, CF₃), 77.1 (m, 1C, ²J_(CF)=28 Hz, COH), 72.3 (s, 2C,CH), 54.7 (s, 1C, NCH₂), 52.6 (s, 2C, CH), 45.6 (s, 1C, CH₂), 33.2 (s,2C, CH_(2(COD))), 30.4 (s, 2C, CH_(2(COD))), 23.3 (s, 1C, NCH₂CH₂), 21.9(s, 1C, CH₂), 11.1 (s, 1C, NCH₂CH₂CH₂). ¹⁹F NMR (C₆D₆, 298K): δ −76.15(s, 6F, CF₃). Anal. Calcd. for C₁₇H₂₄F₆IrNO: C, 36.16; H. 4.28. Found:C, 36.17; H, 4.34.

Example 3

Synthesis of [Ir(COD)(FBC4)₂], R¹=Me.

The procedures were identical to that of example 1, using 0.2 g of[Ir(COD)(μ-Cl)]₂ (0.29 mmol), 0.14 g of aminoalcohol HO(CF₃)₂CH₂NMe₂(0.64 mmol), 0.1 g of NaOH and 50 mL of THF. After removal of THF, theresidue was extracted with pentane (2×20 mL), and the pentane solutionwas evaporated under vacuum to give 0.25 g of yellow solid[Ir(COD){O(CF₃)₂CH₂NMe₂}] (yield 82%), which was further purified byvacuum sublimation at 57° C. and 150 mtorr.

Spectral data: MS (EI, ¹⁹³Ir), m/z 525, M⁺. ¹H NMR (C₆D₆, 298K): δ4.48˜4.45 (m, 2H, CH_((COD))), 2.72˜2.69 (m, 2H, CH_((COD))), 2.39 (s,1H, CH₂), 2.18˜2.02 (m, 4H, CH_(2(COD))), 1.80 (s, 6H, CH₃), 1.43˜1.37(m, 4H, CH_(2(COD))). ¹³C NMR (CDCl₃, 298K): δ 124.72 (q, 2C,¹J_(CF)=290 Hz, CF₃), 88.87 (m, 1C, ²J_(CF)=27 Hz, CO), 67.01 (s, 2C,CH_((COD))), 65.60 (s, 1C, NCH₂), 54.10 (s, 2C, CH_((COD))), 50.53 (s,2C, CH₃), 32.44 (s, 2C, CH_(2(COD))), 30.34(s, 2C, CH_(2(COD))). ¹⁹F NMR(C₆D_(6, 298)K): δ −77.34 (s, 6F, CF₃). Anal. Calcd. for C₁₄H₂₀F₆IrNO:C, 32.06; H, 3.84. Found: C, 31.34; H, 3.96.

Example 4

Synthesis of [Ir(CO)₂(FBC4)₂], R¹=Me.

Sodium hydroxide (24 mg, 1.0 mmol) was suspended in 20 mL of THF. Tothis was slowly added 0.14 g of aminoalcohol HO(CF₃)₂CH₂NMe₂ (0.64 mmol)in THF (20 mL). The mixture was stirred at room temperature for 40 min.The solution was then filtered and the filtrate was transferred into a100 mL reaction flask containing a suspension of [Ir(COD)(μ-Cl)]₂ (0.2g, 0.29 mmol) in THF (20 mL). This mixture was further stirred at roomtemperature for 4 hours, giving a yellowish brown solution alone with anoff-white NaCl precipitate. The solution was then purged with a slowstream of CO gas for 5 min., during which time the color graduallychanged from brown to yellow, indicating completion of the COsubstitution. The solution was filtered, the filtrate was thenconcentrated, and the resulting oily residue was taken into 35 mL ofhexane. Evaporation of hexane and sublimation at 42° C. and 3 torr gave0.14 g of light-yellow iridium compound [Ir(CO)₂{O(CF₃)₂CH₂NMe₂}] (0.30mmol, 51%).

Spectral data: MS (EI, ¹⁹³Ir), m/z 473, M⁺. ¹H NMR (CDCl₃, 298K): δ 3.08(s, 6H, N(CH₃)₂), 3.04 (s, 2H, CH₂). ¹³C NMR (CDCl₃, 298K): δ 171.8 (s,1C, CO), 169.1 (s, 1C, CO), 123.6 (q, 1C, ¹J_(CF)=348 Hz, CF₃), 88.3 (m,1C, ²J_(CF)=29 Hz, C(CF₃)), 63.8 (s, 1C, NCH₂), 55.0 (s, 2C, CH₃). ¹⁹FNMR (C₆D₆, 298K): δ −76.17 (s, 6F, CF₃). Anal. Calcd. for C₈H₈F₆IrNO₃:C, 20.34; H, 1.71. Found: C, 20.43; H, 1.92.

Example 5

Synthesis of [Ru(NBD)(FBC1)₂], R=CF₃.

To a 100 mL reaction flask, was charged 1.0 g of [Ru(NBD)Cl₂]_(x) (3.8mmol), six equiv. of (hfac)Na (5.23 g, 22.7 mmol) and 60 mL of THF. Themixture was then heated to reflux for 20 days, during which time thesolution gradually changed from brown color to red. After stopping thereaction, the solution was filtered and the filtrate was concentrated todryness. The resulting solid residue was purified by sublimation (150mtorr, 45° C.), giving 1.36 g of Ru(NBD)(hfac)₂ as red solid (2.24 mmol,59%).

Spectral data: MS (EI, ¹⁰²Ru): m/z 608 (M⁺). ¹H NMR: (400 MHz, CDCl₃,298 K): δ 6.13 (s, 2H, CH), 5.40 (m, 2H, CH_((NBD))), 4.84 (m, 2H,CH_((NBD))), 4.04 (m, 2H, CH_((NBD))), 1.77 (s, 2H, CH₂). ¹³C NMR:(125.7 MHz, d-acetone, 298 K): δ 175.5 (q, 2C, CCF₃, ²J_(CF)=36 Hz),175.4 (q, 2C, CCF₃, ²J_(CF)=36 Hz), 116.3 (q, 2C, CF₃, ¹J_(CF)=285 Hz),116.0 (q, 2C, CF₃, ¹J_(CF)=284 Hz), 90.6 (s, 2C, CH), 82.3 (s, 2C,CH_((NBD))), 79.6 (s, 2C, CH_((NBD))), 62.3 (s, 2C, CH_((NBD))), 51.5(s, 1C, CH₂). ¹⁹F (470.3 MHz, CDCl₃, 298 K): δ −75.13 (s, 6F, CF₃),−75.75 (s, 6F, CF₃). Anal. Calcd. for C₁₇H₁₀F₁₂O₄Ru: C, 33.62; H, 1.66.Found: C, 33.82; H, 2.15.

Example 6

Synthesis of [Ru(COD)(FBC4)₂], R¹=H.

Sodium hydride (70 mg, 3 mmol) was suspended in 20 mL of THF. To thiswas added dropwise 0.38 g of the aminoalcohol ligand HOC(CF₃)₂CH₂NH₂(1.9 mmol) in THF (20 mL). The mixture was further stirred for 40 min.until evolution of gas had ceased. The filtrate was then transferredinto a 100 mL reaction flask containing a suspension of [Ru(COD)Cl₂]_(x)(0.15 g, 0.55 mmol) in THF solution (20 mL). This mixture was heated toreflux for 48 hours, giving a brown solution alone with an off-whiteNaCl precipitate. After cooling to room temperature, the mixture wasfiltered and the filtrate was concentrated to dryness. The solid residuewas purified by column chromatography on silica gel using ethyl acetateas eluent and the resulting orange solid was then sublimed under vacuum(250 mtorr, 150° C.), giving 0.23 g of light yellow[Ru(COD){OC(CF₃)₂CH₂NH₂}₂] (0.38 mmol, 70%).

Spectral data: MS (EI, ¹⁰²Ru): m/z 602 (M⁺). ¹H NMR (300 MHz, d-acetone,298 K): δ 5.37 (s, 2H, NH), 5.18 (s, 2H, NH), 3.63 (m, 4H, NCH₂), 3.38(m, 2H, CH_((COD))), 3.30 (m, 2H, CH_((COD))), 2.51 (m, 2H,CH_(2(COD))), 2.30 (m, 2H, CH_(2(COD))), 2.15 (m, 2H, CH_(2(COD))), 1.81(m, 2H, CH_(2(COD))). ¹³C NMR (125.7 MHz, d-acetone, 298 K): δ 124.9 (q,2C, CF₃, ¹J_(CF)=296 Hz), 124.6 (q, 2C, CF₃, ¹J_(CF)=292 Hz), 83.2 (m,2C, C(CF₃)₂, ²J_(CF)=26 Hz), 79.4 (s, 2C, CH_((COD))), 76.5 (s, 2C,CH_((COD))), 52.2 (s, 2C, NCH₂), 30.3 (s, 2C, CH_(2(COD))), 28.3 (s, 2C,CH_(2(COD))). ¹⁹F (470.3 MHz, acetone-d₆, 298 K): δ −76.60 (s, 6F, CF₃),−76.62 (s, 6F, CF₃). Anal. Calcd. for C₁₆H₂₀F₁₂N₂O₂Ru: C, 31.95; H,3.35; N, 4.66. Found: C, 32.12; H, 3.80; N, 4.60.

Example 7

Synthesis of [Ru(COD)(FBC4)₂], R¹=Et.

The procedures were identical to that of example 6, using 0.46 g of[Ru(COD)Cl₂]_(x) (1.7 mmol), 1.03 g of aminoalcohol ligandHOC(CF₃)₂CH₂NHEt (4.58 mmol) and slightly excess of sodium hydride.After removal of solvent, the solid residue was then purified by columnchromatography on silica gel using a 2:1 mixture of hexane and CH₂Cl₂ aseluent and the resulting orange solid was sublimed under vacuum (250mtorr, 90° C.), giving 0.85 g of orange [Ru(COD){OC(CF₃)₂CH₂NHEt}₂](1.29 mmol, 76%).

Spectral data: MS (EI, ¹⁰²Ru): m/z 658 (M⁺). ¹H NMR (400 MHz, CDCl₃, 298K): δ 4.09 (m, 2H, CH_((COD))), 3.69 (m, 2H, CH_((COD))), 3.47 (m, 2H,CH₂CH₃, ³J_(HH)=7.2 Hz), 3.40 (m, 2H, NCH₂), 2.80 (s, 2H, NH), 2.66 (m,2H, NCH₂), 2.53 (m, 2H, CH_(2(COD))), 2.20 (m, 2H, CH_(2(COD))), 2.08(m, 2H, CH₂CH₃, ³J_(HH)=7.2 Hz), 2.06 (m, 2H, CH_(2(COD))), 1.81 (m, 2H,CH_(2(COD))), 1.17 (t, 6H, CH₃, ³J_(HH)=7.2 Hz). ¹³C NMR (125.7 MHz,CDCl₃, 298 K): δ 125.4 (q, 2C, CF₃, ¹J_(CF)=293 Hz), 124.1 (q, 2C, CF₃,¹J_(CF)=291 Hz), 93.9 (s, 2C, CH_((COD))), 85.4 (m, 2C, C(CF₃)₂,²J_(CF)=27 Hz), 82.2 (s, 2C, CH_((COD))), 53.8 (s, 2C, NCH₂), 45.9 (s,2C, CH₂CH₃), 30.9 (s, 2C, CH_(2(COD))), 27.2 (s, 2C, CH_(2(COD))), 13.9(s, 2C, CH₃) ¹⁹F (470.3 MHz, CDCl₃, 298 K): δ −76.81 (q, 6F, CF₃,⁴J_(FF)=10.8 Hz), −77.50 (q, 6F, CF₃, ⁴J_(FF)=10.8 Hz). Anal. Calcd. forC₂₀H₂₈F₁₂N₂O₂Ru: C, 36.53; H, 4.29; N, 4.26. Found: C, 36.42; H, 4.30;N, 4.44.

Example 8

Synthesis of [Ru(FBC2)₃], R=CF₃, R¹=Me.

Sodium hydride (50 mg, 2.08 mmol) was suspended in 20 mL of THF. To thiswas added dropwise 0.38 g of the β-ketoimine ligandHOC(CF₃)═CHC(CF₃)═NMe, (hfim, 1.72 mmol) in THF (20 mL). The mixture wasstirred for 40 min. at room temperature until evolution of gas hadceased. The solution was then filtered to remove the excess NaH, andfiltrate was transferred into a 100 mL reaction flask containing asuspension of [Ru(COD)Cl₂]_(x) (0.15 g, 0.54 mmol) in THF solution (60mL). This mixture was heated to reflux for 48 hours, giving a dark-greensolution along with an off-white NaCl precipitate. After allowing thesolution to cool to room temperature, the mixture was filtered and thefiltrate was concentrated to dryness. The solid residue was purified bycolumn chromatography on silica gel eluting with a 1:3 mixture of CH₂Cl₂and hexane, giving 0.23 g of [Ru(hfim)₃] (0.30 mmol, 56%) as greensolid. Further purification was carried out using sublimation at 60°C./400 mtorr, m.p.=127° C.

Selected data: MS (EI, 70 eV, L=C₆H₄F₆NO), observed (actual)[assignment]: 762 (762) [RuL₃], 541 (541) [[RuL₂], 321 (321) [RuL], 220(220) [L]. Anal. calcd. for C₁₈H₁₂F₁₈N₃O₃Ru: C, 28.40; H, 1.59; N, 5.52.Found: C, 28.75; H, 1.79; N, 5.23.

Example 9

Synthesis of [Ru(FBC2)₃], R=Me, R¹=Me.

The synthetic procedures were essentially identical to that of example8, using 0.40 g of [Ru(COD)Cl₂]_(x) (1.45 mmol), 0.84 g of theβ-ketoimine ligand HOC(CF₃)═CHC(Me)═NMe (tfim, 5.02 mmol) and 0.16 g ofNaH (6.7 mmol) in 80 mL of THF. After stopping the reaction and removalof the solvent, the resulting solid residue was purified by columnchromatography on silica gel eluting with a 1:1 mixture of CH₂Cl₂ andhexane, giving 0.51 g of [Ru(tfim)₃] (0.85 mmol, 59%) as red solid.Further purification was carried out using sublimation at 60° C./200mtorr, m.p.=195° C.

Selected data: MS (EI, 70 ev, L=C₆H₆F₃NO), observed (actual)[assignment]: 600 (600) [RuL₃], 433 (433) [[RuL₂], 265 (267) [RuL], 166(166) [L]. Anal. Calcd. for C₁₈H₂₁F₉N₃O₃Ru: C, 36.07, H, 3.53, N, 7.01.Found: C, 36.11, H, 3.90, N, 6.98.

Example 10

Synthesis of [Os(CO)₃(CF₃CO₂)(FBC1)], R=CF₃.

Finely crushed [Os(CO)₃(CF₃CO₂)]₂ (0.2 g, 0.26 mmol) and β-diketonateligand (hfac)H (0.32 g, 1.55 mmol) in a 18 mL Carius tube were degassedand the tube sealed under vacuum. After heated at 185° C. for 6 hours,the tube was then cooled and opened. The reaction mixture was extractedwith CH₂Cl₂ to give a yellow-cream solid. Further purification by vacuumsublimation gave [Os(CO)₃(CF₃CO₂)(hfac)] as light yellow solid (0.24 g,0.40 mmol) yield: 77%.

Spectral data: MS (EI, ¹⁹²Os): m/z 483 (M⁺−C₂O₂F₃). IR (C₆H₁₂): ν (CO),2142 (vs), 2066 (vs), 2057 (vs) cm⁻¹. ¹H NMR (400 MHz, acetone-d₆,298K): δ 6.76 (s, 1H, CH). ¹³C NMR (75 MHz, acetone-d₆, 298K): δ 176.0(q, 1C, ²J_(CF)=38 Hz, C(CF₃)), 166.8 (1C, CO), 164.6 (2C, CO), 161.7(q, 1C, ²J_(CF)=38 Hz, C(CF₃)), 117.0 (q, 2C, ¹J_(CF)=283 Hz, CF₃),115.1(1C, q, ¹J_(CF)=283 Hz, CF₃), 94.4(1C, CH). ¹⁹F NMR (470 MHz,acetone-d₆, 298K): δ −74.07 (s, 3F), −74.61 (s, 6F). Anal. Calcd forC₁₀HF₉O₇Os: C, 20.21; H, 0.17. Found: C, 20.25; H, 0.25.

Example 11

Synthesis of [Os(CO)₃(CF₃CO₂)(FBC1)], R=t-Bu.

Finely crushed [Os(CO)₃(CF₃CO₂)]₂ (0.5 g, 0.65 mmol) and (tdhd)H ligand(1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione, 0.76 g, 3.87 mmol) in a18 mL Carius tube were degassed and the tube sealed under vacuum. Afterheated at 185° C. for 6 hours, the tube was then cooled and opened. Thereaction mixture was extracted with CH₂Cl₂ to give a yellow-cream solid.Further purification by vacuum sublimation (220 mtorr, 45° C.) gave[Os(CO)₃(CF₃CO₂)(tdhd)] as light yellow solid (0.59 g, 1.01 mmol) yield:78%. Single crystals were grown from a 1:1 mixture of CH₂Cl₂ and hexaneat room temperature.

Spectral data: MS (EI, ¹⁹²Os), m/z 584 (M⁺). IR (C₆H₁₂): ν (CO), 2132(vs), 2057 (vs), 2040 (vs) cm⁻¹. ¹H NMR (400 MHz, CDCl₃, 294K): δ 6.23(s, 1H, CH), 1.19 (s, 9H, ^(t)Bu). ¹³C NMR (100 MHz, CDCl₃, 294K): δ207.4 (1C, C(CF₃)), 169.0 (q, 1C, ²J_(CF)=35 Hz, C(CF₃)), 168.2 (1C,CO), 165.6 (1C, CO), 165.1 (1C, CO), 162.3 (q, 1C, ²J_(CF)=38 Hz,C(CF₃)), 117.6 (q, 1C, ¹J_(CF)=281 Hz, CF₃), 114.7(q, 1C, ¹J_(CF)=286Hz, CF₃), 94.3 (1C, CH), 43.4 (1C, CMe₃), 27.4 (3C, Me). ¹⁹F NMR (470.3MHz, CDCl₃, 298K): δ −74.46 (s, 3F), −74.51 (s, 3F). Anal. Calcd forC₁₃H₁₀F₆O₇Os: C, 26.81; H, 1.73. Found: C, 26.96; H, 2.19.

Example 12

Synthesis of [Os(CO)₃Br(FBC1)], R=t-Bu.

Finely crushed [Os(CO)₃(μ-Br)]₂ (0.1 g, 0.13 mmol) and (tdhd)H (0.15 g,0.77 mmol) in a 10 mL Carius tube were degassed and the tube sealedunder vacuum. After heated at 185° C. for 6 hours, the tube was thencooled and opened. The reaction mixture was extracted with CH₂Cl₂ togive a yellow-cream solid. Further purification by vacuum sublimation(250 mtorr, 70° C.) gave [Os(CO)₃Br(tdhd)] as light yellow solid (0.10g, 0.19 mmol), yield: 73%. Single crystals were grown from a 1:1 mixtureof CH₂Cl₂ and hexane at room temperature.

Spectral data: MS (EI, ¹⁹²Os), m/z 550 (M⁺). IR (C₆H₁₂): ν (CO), 2123(s), 2047 (vs), 2030 (vs) cm⁻¹. ¹H NMR (400 MHz, CDCl₃, 294K): δ 6.19(s, 1H, CH), 1.21 (s, 9H, ^(t)Bu). ¹³C NMR (100 MHz, CDCl₃, 294K): δ206.6 (1C, CO), 168.5 (q, 1C, ²J_(CF)=34 Hz, C(CF₃)), 166.7 (1C, CO),166.3 (1C, CO), 165.2 (1C, CO), 117.4 (q, 1C, ¹J_(CF)=283 Hz, CF₃), 94.9(1C, CH), 43.0 (1C, CMe₃), 27.5 (3C, Me). ¹⁹F NMR (470.3 MHz, CDCl₃,298K): δ −74.75 (s, 3F). Anal. Calcd for C₁₁H₁₀BrF₃O₅Os: C, 24.05; H,1.83. Found: C, 22.84; H, 2.61.

Example 13

Synthesis of [Os(CO)₃I(FBC1)], R=t-Bu.

Finely crushed [Os(CO)₃(μ-I)]₂ (0.1 g, 0.11 mmol) and (tdhd)H (0.13 g,0.69 mmol) in a 10 mL Carius tube were degassed and the tube sealedunder vacuum. After heated at 185° C. for 6 hours, the tube was thencooled and opened. The reaction mixture was extracted with CH₂Cl₂ togive a yellow solid. Further purification by vacuum sublimation (120mtorr, 55° C.) gave [Os(CO)₃I(tdhd)] as light yellow solid (0.10 g, 0.17mmol), yield: 76%. Single crystals were grown from a 1:1 mixture ofCH₂Cl₂ and hexane at room temperature.

Spectral data: MS (EI, ¹⁹²Os), m/z 598 (M⁺). IR (C₆H₁₂): ν (CO), 2119(s), 2044 (vs), 2030 (vs) cm⁻¹. ¹H NMR (400 MHz, CDCl₃, 294K): δ 6.20(s, 1H, CH), 1.20 (s, 9H, ^(t)Bu). ¹³C NMR (100 MHz, CDCl₃, 294K): δ206.7 (1C, CO), 168.6 (q, 1C, ²J_(CF)=33 Hz, C(CF₃)), 167.3 (1C, CO),166.9 (1C, CO), 163.7 (1C, CO), 117.2 (q, 1C, ¹J_(CF)=272 Hz, CF₃), 95.6(1C, CH), 42.8 (1C, CMe₃), 27.5 (3C, Me). ¹⁹F NMR (470.3 MHz, CDCl₃,298K): δ −74.86 (s, 3F). Anal. Calcd for C₁₁H₁₀F₃IO₅Os: C, 22.16; H,1.69. Found: C, 26.64; H, 2.13.

Example 14

CVD of the Corresponding Metal Thin-film

Typically, the iridium, ruthenium and osmium thin-films may be preparedby chemical vapor deposition at about 300–500° C. and about 400–2000mtorr in a typical cold-wall reactor. In this example, the complexes 2,4˜8 and 11˜14 were used as the source reagents and the run conditionsare listed in Tables 5 and 6. Growth of smooth metallic thin films wasrealized on Si wafer and Pyrex glass substrates. The deposited filmswere found to be highly reflective with good adhesion to all substrates.The composition of the films was determined by Auger/ESCA analysis. Theelectrical resistivity of films was measured by a four-point probemethod at room temperature.

TABLE 5 Selected CVD parameters for experiments using iridium complexesas source reagents and pyrex glass and Si wafer as substrates T_(R)T_(D) R_(D) Contents (at. %) and Resistivity ρ Compound CG_(FR) (sccm)(° C.) (° C.) (Å/min) (μΩ-cm) 2 O₂ (40 sccm) 80 400 70 Ir, 98%; O, 2%. ρ= 10.2. 4 O₂ (20 sccm) 80 375 38 Ir, 99%; O, 1%. ρ = 8.4. 5 O₂ (20 sccm)80 350 53 Ir, 98%; O, 2%. ρ = 9.6. 6 O₂ (20 sccm) 70 400 110 Ir, 96%; O,4%. ρ = 19.3. 7 O₂ (20 sccm) 70 350 66 Ir, 99%; O, 1%. ρ = 6.8. 8 O₂ (20sccm) 70 400 68 Ir, 97%; C, 1%; O, 2%. ρ = 13.9. Compound number isidentical to those of the entry number listed in Tables 3 and 4.Abbreviations: CG_(FR) = carrier gas flow rate, T_(R) = temperature ofprecursor reservoir, T_(D) = deposition temperature and R_(D) =deposition rate.

TABLE 6 Selected CVD parameters for experiments using ruthenium orosmium complexes as source reagents and pyrex glass and Si wafer assubstrates CG_(FR) P_(S) T_(R) T_(D) R_(D) Contents (at. %) and Compound(sccm) (torr) (° C.) (° C.) (Å/min) Resistivity ρ (μΩ-cm) 9 H₂ (10 sccm)2 55 450 30 Ru, 94.5%; C, 2.5%; O, 3%. ρ = 14.1. 11 O₂/Ar (10 sccm) 0.25110 425 14 Ru, 59%; C, 41%. ρ = 10.2. 12 O₂/Ar (15 sccm) 1 80 450 30 Ru,94.8%; O, 5.2%. ρ = 10.5. 12 O₂ (20 sccm) 2 70 325 21 ρ = 201.0. 13O₂/Ar (30 sccm) 0.5 130 425 17 Ru, 98%; C, 0.2%; O, 1.8%. ρ = 14.5 13 O₂(50 sccm) 0.5 130 425 114 ρ = 151.4 14 H₂ (15 sccm) 1 90 400 100 Os,96%; C, 3%; O, 1%. ρ = 31.0. Compound number is identical to those ofthe entry number listed in Tables 3 and 4. Abbreviations: CG_(FR) =carrier gas flow rate, P_(S) (torr) = system pressure, T_(R) =temperature of precursor reservoir, T_(D) = deposition temperature andR_(D) = deposition rate.

1. A noble metal organometallic complex of general formula (I):[ML_(a)X_(b)(FBC)_(c)]  (I) wherein M is a noble metal; L is a neutralligand selected from the group consisting of carbonyl, alkene, diene andderivatives of alkenes and dienes additionally containing alkyl orfluorinated alkyl substituents; X Is an anionic ligand; wherein a is aninteger of from zero (0) to three (3), b is an integer of from zero (0)to one (1) and c is an integer of from one (1) to three (3); FBC ligandis a fluorinated bidentate chelate ligand selected from the groupconsisting of a beta-ketoiminate (FBC2), imino-alcoholate (FBC3) andamino-alcoholate (FBC4) having the structural formula indicated below:

wherein R is a C1–C4 alkyl or trifluoromethyl; R¹ is a C1–C6 alkylgroup, which may be substituted by a C1–C4 alkoxy group, and whereinFBC4, one of the R¹ groups may be H.
 2. A compound according to claim 1,wherein the anionic ligand is chloride, bromide, iodide ortrifluoroacetate.
 3. A compound according to claim 2, wherein R ismethyl, t-butyl or trifluoromethyl.
 4. A compound according to claim 3,wherein R¹ is methyl, ethyl, allyl, n-propyl, i-propyl, n-butyl, i-butylor 2-methoxyethyl.
 5. A compound according to claim 1, wherein the noblemetal is selected from the group consisting of iridium, ruthenium andosmium.
 6. A compound according to claim 5, wherein the transition metalis iridium.
 7. A compound selected from the group consisting of[IrL_(a)(FBC2)]  (II),[IrL_(a)(FBC3)]  (III)and[IrL_(a)(FBC4)]  (IV) wherein L is a neutral ligand selected from thegroup consisting of carbonyl, alkene, diene or derivatives of alkenesand dienes additionally containing at least one alkyl or fluorinatedalkyl substituent; a is an integer of one or two, depending on the donorbonding of the selected ligand; FBC ligand is a fluorinated bidentatechelate ligand selected from the group consisting of beta-keloiminate,imino-alcoholate (FBC3) and amino-alcoholate (FBC4) having thestructural formula indicated below:

wherein R is C1–C4 alkyl or trifluoromethyl; R¹ is C1–C6 alkyl, whichmay be substituted by a C1–C4 alkoxy group, and wherein FBC4, one of theR¹ groups may be H.
 8. A compound according to claim 7, wherein R ismethyl, t-butyl or trifluoromethyl.
 9. A compound according to claim 8,wherein R¹ is methyl, ethyl, allyl, n-propyl, i-propyl, n-butyl, i-butylor 2-methoxyethyl.
 10. A compound selected from the group consisting of[RuL_(a)(FBC1)₂]  (V),[RuL_(a)(FBC4)₂]  (VI)and[RuL_(a)(FBC2)₃]  (VII) wherein L is a neutral ligand selected from thegroup consisting of a cyclic diene selected from COD and NBD, orderivatives of a cyclic diene additionally containing at least one alkylor fluorinated alkyl substituent; a is one or zero, depending on the(FBC) ligand selected for the reactions; FBC ligand is a fluorinatedbidentate chelate ligand selected from the group consisting ofbeta-diketonate (FBC1), beta-ketoiminate (FBC2) and amino-alcoholate(FBC4) having structural formula indicated below:

wherein R is C1–C4 alkyl, or trifluoromethyl; R¹ is a C1–C6 alkyl group,which may be substituted by a C1–C4 alkoxy group, and wherein (FBC4), R¹may be H.
 11. A compound according to claim 10, wherein R is methyl,t-butyl or trifluromethyl.
 12. A compound according to claim 11, whereinR¹ is methyl, ethyl, allyl, n-propyl, i-propyl, n-butyl, i-butyl or2-methoxyethyl.
 13. A compound of the general formula VIII[OsL_(a)X(FBC)]  (VIII) wherein L represents carbonyl ligand; a has aconstant value of three (3), X is an anionic monodentate ligand; FBCligand is a fluorinated bidentate chelate ligand selected from:(hfac)=hexafluoroacetylacetonate, (tfac)=trifluoroacetylacetonate, and(tdhd)=1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionate.
 14. A compoundaccording to claim 13, wherein X is chloride, bromide, iodide ortrifluoroacetate.
 15. A method for making a noble metal organometalliccomplex of general formula (I) as defined in claim 1, comprising (a)reacting the respective FBC ligand with a suitable metal hydride,followed by (b) treatment of the product so formed with a metal halidesalt of the desired metal.
 16. A method according to claim 15, whereinthe metal hydride is sodium hydride.
 17. A method according to claim 16,wherein the metal halide salt is [Ir(COD)(μ-Cl)]₂ whereinCOD=1,5-cyclooctadiene; [Os(CO)₃(μ-X)]₂ wherein X=CF₃CO₂, Cl, Br or I;[Ru(CO)Cl₂]_(x) wherein COD=1,5-cyclooctadiene; and [Ru(NBD)Cl₂]_(x),wherein NBD=2,5-norbornadiene.
 18. A method for the chemical vapordeposition of a thin film of a noble metal on a substrate, wherein thethin film is formed on the substrate by depositing a compound of formulaI as defined in claim 1, under an inert gas atmosphere, wherein theinert gas is selected from the group consisting of N₂,He and Ar.
 19. Amethod according to claim 18, wherein the noble metal is selected fromthe group consisting of iridium, ruthenium and osmium.
 20. A methodaccording to claim 18, and wherein the noble metal thin film isconverted to a thin film selected from the group consisting of IrO₂,RuO₂ and OsO₂.
 21. A method for the chemical vapor deposition of a thinfilm of a noble metal on a substrate, wherein the thin film is formed onthe substrate by depositing a compound of formula I as defined in claim1 in the presence of H₂.